The present invention relates to an input processing system for inputting string data including "kanji (Chinese characters)" in a computer system or a wordprocessor. More particularly, the present invention relates to an input processing system employing a scheme for inputting kanji as phonetic data and converting the phonetic data to a corresponding kanji character so as to obtain a desired kanji character, wherein a proper word (or a phrase) is selected from a plurality of homonyms in conversion from phonetic data to the corresponding kanji character, thereby simplifying input operations.
Japanese wordprocessors have been recently very popular among domestic users, as well as Japanese in foreign countries and foreigners who learn Japanese. In a conventional input processing system used in a Japanese wordprocessor, phonetic data constituting a sentence, a phrase, or a clause including kanji is input in units of words, clauses or sets of clauses and converted into a character string including both kanji characters (ideographic characters used in written Japanese) and kana (Japanese phonetic characters used in only written Japanese). Kana characters are classified into "hiragana" and "katakana" characters, which are properly selected according to Japanese usage. Since these kana characters are phonetic symbols, they directly correspond to phonetic data. Kanji characters have an etiological origin in Chinese. Ordinary Japanese sentences, phrases, or clauses are written by character strings including kanji and kana characters. The phonetic data is input by kana characters or alphabetic character strings representing Japanese phonetic symbols. In conversion from phonetic data to a character string including kanji and kana characters, a kana-to-kanji conversion dictionary as a conversion data base is retrieved. This dictionary is a data base which uses phonetic data as a key to search a kanji character string or a character string including kanji and kana characters.
Since the Japanese language includes a lot of homonyms, a plurality of conversion possibilities or candidates are often listed in kana/kanji conversion. In a conventional system, if a plurality of conversion possibilities are present, an operator operates a key for switching a possibility display from one to another among the selected conversion possibilities, that is, the next conversion possibility key is operated to display the correct word (or phrase) among the plurality of possibilities. When the proper possibility is displayed, it is selected as the conversion result.
However, selection operation for homonyms is cumbersome and time-consuming. In a conventional system, the previous selection frequencies of homonyms are sequentially checked, and the priority order of the conversion possibilities is determined according to the order of frequencies. For an identical combination of homonyms, a word (or a phrase) which has been most frequently selected in the preceding operations is displayed as the first conversion possibility. In another conventional system, since identical words are frequently repeated in a single sentence, the immediately preceding or last selected word (or phrase) is displayed as the first conversion possibility.
These systems greatly reduce operation load, and more particularly, the number of key depressions in homonymic selection.
However, different homonyms often appear in a single sentence. According to the frequency check scheme described above, the conversion possibility having a higher frequency is selected although a conversion possibility having the lowest frequency is to be selected. According to the last conversion possibility selection scheme, homonymic selection must be performed whenever the corresponding phonetic data appears. The above implementations result in inconvenience.
It may be possible to introduce syntactic analysis of machine translation techniques into input processing for selecting homonyms. However, since the syntactic analysis is performed in units of sentences, it cannot be applied to an input processing system for converting kana characters into kanji characters in units of words or clauses.
An improved conventional input processing system used in a Japanese wordprocessor is also available. According to this system, phonetic data without segmentation is input, segmented in the system, and sequentially subjected to kana-kanji conversion. However, in practice, the number of characters constituting phonetic data input by a single operation cycle is limited due to the limitations of number of data which can be processed in combination in the system. According to still another system, phonetic data segmentation in units of words or clauses from the beginning of the sentence is automatically detected by the system, and kana-kanji conversion is performed in units of detected segmentations.
Even if one sentence is input, it is segmented into words or clauses which are then converted from kana characters to kanji characters. Therefore, syntactic analysis of the entire sentence cannot be applied to the conventional input processing systems.
In addition, in order to perform the syntactic analysis, one sentence must be completely input. If one sentence is not completely input, the conversion result cannot be obtained. It takes a long period of time to obtain the conversion result after the sentence input is started. If phonetic data is input while a document is being drafted, the already input data (corresponding to a portion whose conversion result is not displayed yet) cannot be checked.